LG Soundbar HDMI ARC Not Working — Fix

What it means

LG soundbar HDMI ARC not working is caused by SimpLink (HDMI-CEC) being disabled on the LG TV, using a non-ARC HDMI port, or a cable that does not support ARC.
Enable SimpLink and use the ARC-labelled port.

How to Fix It

Use the HDMI ARC port on the TV

Only one HDMI port on LG TVs supports ARC — it is labelled ARC (usually HDMI 2).
Plugging the soundbar into a regular HDMI port will not carry audio back to the soundbar.
Enable SimpLink on LG TV

Go to Settings > General > SIMPLINK (HDMI-CEC) > On.
Also set Auto Power Sync to On.
Without SimpLink the LG TV will not recognise the soundbar via HDMI ARC.
Set Sound Out to HDMI ARC

On LG TV: Settings > Sound > Sound Out > select HDMI ARC or LG Sound Sync.
Some LG TVs auto-detect the soundbar.
If not, select it manually from the list.
Use a High Speed HDMI cable

Use a cable rated High Speed HDMI or HDMI 2.0.
Older standard-speed cables may not carry the audio return channel signal and cause ARC to fail silently.
Power cycle both devices

Unplug the soundbar and the TV from the wall for 60 seconds.
Reconnect the HDMI cable, power on the TV first, then the soundbar.
Wait 20 seconds for ARC to negotiate.
Update LG TV firmware

LG TV firmware updates frequently address ARC compatibility issues.
Go to Settings > General > About This TV > Check for Updates and install any available update.

Frequently Asked Questions

LG TV does not detect soundbar via HDMI ARC?

Confirm SimpLink is On, Auto Power Sync is On, and the cable is in the ARC-labelled port.
If the TV still does not detect the soundbar, try a different HDMI cable.

LG soundbar HDMI ARC drops audio randomly?

Random audio drops are almost always caused by a marginal cable.
Try a new certified Premium High Speed HDMI cable and update both TV and soundbar firmware.

Non-LG TV with LG soundbar — ARC not working?

Enable HDMI-CEC on your non-LG TV (called Anynet+ on Samsung, Bravia Sync on Sony).
Then set TV audio output to HDMI ARC in TV sound settings.